This application is based on and incorporates herein by reference Japanese Patent Application Nos. Hei. 11-311126 filed on Nov. 1, 1999, 2000-22529 filed on Jan. 31, 2000, and 2000-147238 filed on May 19, 2000.
1. Field of the Invention
The present invention relates to a rotation angle detector suitable for use in a throttle position sensor of a vehicle.
2. Description of Related Art
JP-A-62-182449 discloses a throttle position sensor in which an insulating plate having a variable resister is fixed to the end of a throttle valve shaft. The insulating plate rotates with the throttle valve shaft. A throttle position signal is output from a terminal fixed at a sensor cover side of the throttle position sensor.
However, in JP-A-62-182449, since the terminal is mechanically fixed to the throttle position sensor, the terminal is not appropriately positioned with respect to the insulating plate, thereby reducing a detecting accuracy of the throttle valve opening degree.
JP-A-2-130403 discloses a throttle position sensor in which a permanent magnet and a yoke are fixed to a throttle valve shaft. The permanent magnet and the yoke rotate with the throttle valve shaft. A Hall element detecting a rotation angle of the throttle valve and a signal calculate circuit are disposed on a board, and are connected to a connector through a lead frame. A throttle position signal is output through the connector.
However, in JP-A-2-130403, the board, the lead frame, and the connector are integrated by resin, and this integrated member is mechanically screwed to a throttle body, so that the throttle valve shaft may slide in the axial direction thereof.
A first object of the present invention is to accurately position a magnetic sensing element with respect to a magnet for improving an accuracy of detecting a rotation angle. A second object of the present invention is to easily connect the magnetic sensing element and an outside connection terminal.
According to a first aspect of the present invention, a resin molded member integrates and supports a non-contact type magnetic sensing element and an output terminal by resin molding. Thus, the magnetic sensing element and the output terminal are accurately positioned. As a result, when a resin molded member supporting a sensor unit including the magnetic sensing element is attached to a rotary member, a gap between the magnetic sensing element and a magnet disposed in the rotary member is accurately attained, thereby improving an accuracy of detecting a rotation angle of the rotary member.
According to a second aspect of the present invention, a first resin molded member integrating and supporting a non-contact type magnetic sensing element and an output terminal by resin molding and a stator core strengthening a magnetic force around the non-contact type magnetic sensing element are integrated and supported by resin molding. Thus, the magnetic sensing element and the output terminal are accurately positioned, thereby improving an accuracy of detecting a rotation angle of a rotary member.
According to a third aspect of the present invention, a condenser is disposed between an outside connection terminal and a ground terminal and connected thereto. Thus, a stable output signal is effectively attained from an electric device, and a stable input signal is effectively supplied into the electric device. Further, since the condenser is supported by a resin molded member of which forming pressure is lower than a general injection pressure, the condenser is not highly pressed, thereby preventing the condenser from separating from the outside connection terminal and the ground terminal.
According to a fourth aspect of the present invention, a stator core includes a first stator core portion made by stacking a plurality of magnetic plates in a thickness direction thereof, a second stator core portion made by stacking a plurality of magnetic plates in a thickness direction thereof, and a non-magnetic plate connecting an end surface of the first stator core portion to an end surface of the second stator core portion. Thus, the width of a magnetic sensing gap formed between the first and second stator core portions are accurately kept without a resin spacer, thereby improving en efficiency of a magnetic circuit. Therefore, the stator core is made by one component combining the magnetic plate and non-magnetic plate, thereby reducing the number of parts and production cost.